It is home to a summer Irish festival celebrating the local families that moved to Ireland. The Melfa river, a left affluent of the Liri river, flows in the commune.

The Roman writer Titus Pomponius Atticus had a villa in what is now the frazione of Montattico. Sights include the medieval Benedictine monastery of Sant'Angelo in Pesco Mascolino, and a Roman bridge above the Melfa. Other Roman remains are in the archaeological site of San Nazario.

In the late 19th and early 20th century a significant number of young people left Casalattico to work in Ireland, with many founding chip shops there. Up to 8,000 Irish-Italians have ancestors from Casalattico and nearby Picinisco

Many of them also emigrated to England, Scotland, France, Belgium and the United States.